Articulation entropy: An unsupervised measure of articulatory precision

Articulatory precision is a critical factor that influences speaker intelligibility. In this paper, we propose a new measure we call ‘articulation entropy’ that serves as a proxy for the number of distinct phonemes a person produces when he or she speaks. The method is based on the observation that the ability of a speaker to achieve an articulatory target, and hence clearly produce distinct phonemes, is related to the variation of the distribution of speech features that capture articulation - the larger the variation, the larger the number of distinct phonemes produced. In contrast to previous work, the proposed method is completely unsupervised, does not require phonetic segmentation or formant estimation, and can be estimated directly from continuous speech. We evaluate the performance of this measure with several experiments on two data sets: a database of English speakers with various neurological disorders and a database of Mandarin speakers with Parkinson’s disease. The results reveal that our measure correlates with subjective evaluation of articulatory precision and reveals differences between healthy individuals and individuals with neurological impairment

Vowel Intelligibility in Children With and Without Dysarthria: An Exploratory Study

Children with dysarthria due to cerebral palsy (CP) present with decreased vowel space area and reduced word intelligibility. Although a robust relationship exists between vowel space and word intelligibility, little is known about the intelligibility of vowels in this population. This exploratory study investigated the intelligibility of American-English vowels produced by children with dysarthria and typically-developing children (TD). Three CP and five TD repeated words with contrastive vowels /i-ɪ/,/æ-ɛ/,/ɑ-ʌ/,/o-u/ produced by a native American-English adult. Adult listeners transcribed the utterances orthographically and rated their ease of understanding. Overall, CP presented with less-intelligible vowels than TD. For CP, a trend was found with the lowest intelligibility for /ɑ/ (CP=7%,TD=66%), /ɪ/ (CP=30%,TD=82%), and /ʌ/ (CP=38%,TD=99%), and more heterogeneous vowel confusions; however, intelligibility differences between vowels did not reach statistical significance. Clinical implications include that, unless further studies show vowel-specific effects, treatment targeting the entire vowel system may be warranted for increasing intelligibility

Acoustic and perceptual speech characteristics of native Mandarin speakers with Parkinson Disease

This study examines acoustic features of speech production in speakers of Mandarin with Parkinson's disease (PD) and relates them to intelligibility outcomes. Data from 11 participants with PD and 7 controls are compared on several acoustic measures. In speakers with PD, the strength of association between these measures and intelligibility is investigated. Speakers with PD exhibited significant differences in fundamental frequency, pitch variation, vowel space, and rate relative to controls. However, in contrast to the English studies, speech rate was consistently slow and most strongly correlated with intelligibility. Thus, acoustic cues that strongly influence intelligibility in PD may vary cross-linguistically

Supplemental Information 1: Original questionnaire administered in southern Chile

Background Hundreds of millions of domestic carnivores worldwide have diverse positive affiliations with humans, but can provoke serious socio-ecological impacts when free-roaming. Unconfined dogs (Canis familiaris) and cats (Felis catus) interact with wildlife as predators, competitors, and disease-transmitters; their access to wildlife depends on husbandry, perceptions, attitudes, and behaviors of pet owners and non-owners. Methods To better understand husbandry and perceptions of impacts by unconfined, domestic carnivores, we administered questionnaires (n = 244) to pet owners and non-owners living in one of the last wilderness areas of the world, the Cape Horn Biosphere Reserve, located in southern Chile. We used descriptive statistics to provide demographic pet and husbandry information, quantify free-roaming dogs and cats, map their sightings in nature, and report experiences and perceptions of the impact of free-roaming dogs and cats on wildlife. We corroborated our results with an analysis of prey remains in dog feces (n = 53). With generalized linear models, we examined which factors (i.e., food provisioning, reproductive state, rural/village households, sex, and size) predicted that owned dogs and cats bring wildlife prey home. Results Thirty-one percent of village dogs (n = 121) and 60% of dogs in rural areas (n = 47) roamed freely day and/or night. Free-roaming dog packs were frequently observed (64% of participants) in the wild, including a feral dog population on Navarino Island. Dogs (31 of 168) brought home invasive muskrats (Ondatra zibethicus) and avian prey, and over half of all cats (27 of 51) brought home mainly avian prey. Birds were also the most harassed wildlife category, affected by one third of all dogs and cats. Nevertheless, dog-wildlife conflicts were hardly recognized (<9% of observed conflicts and suspected problems), and only 34% of the participants thought that cats might impact birds. Diet analysis revealed that dogs consumed livestock (64% of 59 prey occurrences), beavers (Castor canadensis, 14%), and birds (10%). The probability that dogs brought prey to owners’ homes was higher in rural locations and with larger dogs. There was also evidence that cats from rural households and with an inadequate food supply brought more prey home than village cats. Discussion Although muskrat, beavers, and birds were brought home, harassed, or found in dog feces, free-roaming dogs and, to a lesser extent, cats are perceived predominantly in an anthropogenic context (i.e., as pets) and not as carnivores interacting with wildlife. Therefore, technical and legal measures should be applied to encourage neutering, increase confinement, particularly in rural areas, and stimulate social change via environmental education that draws attention to the possibility and consequences of unconfined pet interaction with wildlife in the southernmost protected forest ecoregion of the globe

The effects of intensive voice treatment on speech intelligibility and acoustics of Mandarin speakers with hypokinetic dysarthria due to Parkinson’s disease

Hypokinetic dysarthria is a speech disorder that commonly occurs in individuals with Parkinson’s disease (PD). However, little is known about the speech characteristics and the effects of speech treatment on the speech of Mandarin speakers with hypokinetic dysarthria (henceforth, Mandarin speakers with PD). The purpose of this dissertation was to investigate the effects of intensive voice treatment on the speech intelligibility and acoustics of this population. This dissertation consisted of three papers. The first paper, “Acoustic and perceptual speech characteristics of native Mandarin speakers with Parkinson’s disease,” investigated the general speech characteristics of 11 Mandarin speakers with PD. Intelligibility and acoustic outcomes were reported and compared to seven age- and gender-matched neurologically healthy controls. Findings from this study showed that Mandarin speakers with PD exhibited decreased intelligibility, local pitch variation, vowel space area, speech rate, and rate variation. The second paper, “Effects of Loudness and Rate Manipulation Strategies on Speech Intelligibility and Acoustics of Mandarin Speakers With Parkinson’s Disease,” examined the effects of cueing to increase loudness and reduce speech rate on speech intelligibility and acoustics. Acoustic features including speech intensity, pitch range, pause duration, pause frequency, articulation rate, and vowel space area across 11 Mandarin speakers with PD were analyzed. The relationship between speech intelligibility and acoustic features was reported. Results showed that cueing for loud speech significantly increased intelligibility, but cueing for slow speech did not. Different cues had differential effects on the selected acoustic features. Cueing for loud speech resulted in increased vocal intensity and cueing for slow speech resulted in reduced articulation rate and increased pause frequency. In the loud speaking condition, greater vocal intensity and larger vowel space contributed to increased intelligibility, whereas in the slow condition, increased intensity, vowel space, as well as articulation rate, showed a trend toward contributing to increased intelligibility. The third paper, “The Effects of Intensive Voice Treatment on Intelligibility in Mandarin Speakers with Parkinson’s Disease: Acoustic and perceptual findings,” investigated the short- and long-term effects of intensive voice treatment (Lee Silverman Voice Treatment LOUD) on speech intelligibility and acoustics of nine Mandarin speakers with PD. All speakers showed increased intelligibility from pretreatment to immediate post-treatment, and the improvement was maintained at the 6-month follow-up. Five acoustic features were analyzed. Speech intensity, vowel space, and speech rate changed significantly in positive directions immediately post-treatment, and the increases were retained up to six months. Global pitch variation increased immediately post-treatment but not at the 6-month follow-up. No changes were found in local pitch variation following treatment. Self-reported intelligibility, voice quality, confidence, frustration level, and communicative participation changed positively immediately after the completion of treatment and at the 6-month follow-up. To conclude, the speech characteristics of Mandarin speakers with PD were generally consistent with those of English speakers with PD, except that speech was slower in the Mandarin speakers. Cueing to increase loudness and reduce rate had different effects on speech intelligibility and production, with louder speech yielding greater intelligibility and acoustic benefits. Following intensive voice treatment (LSVT LOUD), Mandarin speakers with PD increased their vocal intensity. Speech intelligibility, vowel space, global pitch variation and speech rate increased as a result of the treatment. Thus, some differences between Mandarin and English dysarthria and effects of cueing might be present, but as for English speakers, intensive treatment (specifically LSVT LOUD) focusing on increasing vocal intensity shows promise for increasing intelligibility and quality of life in Mandarin speakers with hypokinetic dysarthria. Future studies should include a larger number of participants and probe the effects of behavioral speech modifications and intensive voice treatment on lexical tone, and consider which physiological mechanisms might be associated with production of lexical tone, given that lexical tone is often crucial to differentiating word meaning in Mandarin

Identification of Cellular Proteins Important for Jaagsiekte Sheep Retrovirus Transformation

Jaagsiekte sheep retrovirus (JSRV) is the etiologic agent of a contagious lung cancer in sheep, ovine pulmonary adenocarcinoma (OPA). The envelope gene (env) also is an oncogene, since it induces cell transformation and tumors on its own. The subject of this thesis was to identify cellular proteins that interact with JSRV Env and to assess their roles in JSRV transformation. A previous yeast two-hybrid screen identified candidate proteins that can interact with the JSRV envelope protein. Two were studied here: Zinc Finger Protein 111 (Zfp111) and Ribonucleotide Reductase subunit 2 (RRM2). For Zfp111, shRNA knockdown of endogenous zfp111 in rat 208F fibroblasts reduced transformation by JSRV Env but not by another viral oncogene v-mos. Env transformation was restored by a knockdown-resistant Zfp111 cDNA, and over-expression of zfp111 increased transformation by Env but not v-mos. Knockdown of zfp111 decreased proliferation rates of Env transformed cells but not untransformed cells. Zfp111 bound to a smaller form of Env (P70env); while the Env polyprotein (Pr80env) is cytoplasmic, P70env is nuclear. P70env and Pr80env have the same polypeptide backbone, so they differ in glycosylation. Co-expression of Zfp111 with JSRV Env stabilizes both proteins. Selected alanine scanning mutants in the Env cytoplasmic tail (CT) were co-transfected with Zfp111; there was a strong correlation between mutant transformation efficiencies and levels of P70env and Zfp111 detected. The results suggested a putative interaction region for Zfp111 in the Env CT. With regard to RRM2, endogenous RRM2 co-localized with Env by re-localization to the plasma membrane in transfected NIH 3T3 cells. In rat 208F cells, RRM2 knockdown decreased Env transformation, but there was also a decrease (significantly less) in v-mos transformation. RRM2 knockdown cells showed a decrease in overall growth rates, which might explain the effect on v-mos transformation. Progress towards tandem affinity purification (TAP) of JSRV Env-associated cellular proteins is also described. JSRV Env with a C-terminal TAP tag (HBH) was generated. The HBH-tagged Env could transform cells, and it could be successfully purified over Ni2+ and streptavidin columns; JSRV Env peptide sequences (SU and TM) were identified in preliminary TAP/MS experiments